1. Field of the Invention
The present invention relates to a liquid crystal television apparatus. Particularly, the present invention relates to a liquid crystal television apparatus for inputting a video signal formed of an analog signal and displaying an image based on a digital signal to which the video signal is converted.
2. Description of the Related Art
In conventional liquid crystal television apparatuses, when a computer is connected with a display, a level width of an analog video signal a outputted from the computer is registered in a memory. For example, even when the level width is other than 0.7 V and 1.0 V, a value of a contrast control signal outputted from a microcomputer is adjusted so that a white level of an analog signal b, to which the analog video signal a set to a white level is amplified by a video amplifier, is equal to an optimum white level of the analog video signal b, the optimum white level being registered in the memory and adapted for a characteristic of the display. Then, in accordance with relationship between a level width of the analog video signal a and a level width of the analog video signal b, an adequate contrast image is displayed on the display (for example, see patent Document 1). An apparatus similar to the liquid crystal television apparatuses is disclosed in JP-A No. 188195/1992.
Patent Document
JP-A No. 177903/1999
In the conventional liquid crystal television apparatuses, the contrast is adjusted in accordance with the white level, so that this adjustment is in accordance with a test image of one screen having only white. After the adjustment using the test image, the contrast control signal is fixed. Therefore, when a video can be changed, dynamic image quality adjustment adapted for the video is impossible.